When all characters in a comic make or have the same face or expressions used tirelessly and almost in a copy past manner. For example, the very well known (or not) Sunday morning comic strip "Doonesbury" by Gary Trudeau, or the much lesser known (yet still extremely popularized by idiots) "So You're A Cartoonist" by Tom Preston; or the much much lesser known but mostly hated Ctl+Alt+Delete by Buckly.

Don I enjoy your comic very much, but your characters seem to have extreme Doonesbury Syndrome.